In an exemplary vertical alignment (VA) liquid crystal display device, when a picture is displayed, since liquid crystal molecules keep a certain deflection angle, the transmittance of light under different viewing angles is different, as a result, a color cast phenomenon that a user will feel different colors of a picture somewhat when the user views the picture from different viewing angles is caused.
In order to improve the problem of color cast, at present, a common method is to divide the pixel electrode of RGB subpixels in each pixel unit into two independent pixel electrodes, and to apply different drive voltages to the two pixel electrodes respectively to improve the problem of color cast. Due to increase of a number of the pixel electrodes, such method needs to redesign more metal wires or thin film transistors (TFT) elements to drive the display panel, but the metal wires and the TFT elements are light-shading, thus such method will sacrifice a light transmitting aperture area, affect the transmittance of the panel and increase a backlight cost.
In order to avoid the increase of metal wires or TFT elements, another method is to apply two different high and low drive voltage signals to every adjacent two pixel units respectively. Wherein, specifically, at the same moment, the drive voltages of different polarities are applied to every adjacent two subpixels. By adopting such manner, positive and negative polarities of high voltages of the subpixels in a same row will be caused to be not matched, i.e., a number of the subpixels of positive polarity high voltage is inconsistent with a number of the subpixels of negative polarity high voltage in the same row. Hence, due to the influence of stray capacitance, when the number of the subpixels of positive polarity high voltage is more than the number of the subpixels of negative polarity high voltage in the same row, the equivalent voltage of a common voltage Vcom is improved to some extent relative to the original Vcom, as a result, actually charging charges of the subpixels of positive polarity high voltage are reduced, and brightness is reduced, and oppositely, the actually charging charges of the subpixels of negative polarity high voltage are increased, and the brightness is increased, thereby further affecting display colors and picture quality and generating a problem of abnormal picture quality output.